Find Needle in Haystack with JavaScript

Day 20 / 30 – JavaScript Coding Challenge Today’s problem: Length of Last Word Problem: Given a string containing words and spaces, return the length of the last word. Solution: var lengthOfLastWord = function (s) {     let count = 0;     let i = s.length - 1;     while (i >= 0 && s[i] === " ") {         i--;     }     while (i >= 0 && s[i] !== " ") {         i--;         count++;     }     return count; }; #JavaScript #DSA #CodingPractice #100DaysOfCode #ProblemSolving #FrontendDevelopment

Day 9 / 30 - Javascript Coding Problem: Given an integer array nums, a reducer function fn, and an initial value init, return the final result obtained by executing the fn function on each element of the array, sequentially, passing in the return value from the calculation on the preceding element. This result is achieved through the following operations: val = fn(init, nums[0]), val = fn(val, nums[1]), val = fn(val, nums[2]), ... until every element in the array has been processed. The ultimate value of val is then returned. If the length of the array is 0, the function should return init. Please solve it without using the built-in Array.reduce method. Solution: var reduce = function (nums, fn, init) { let numsLength = nums?.length; if (numsLength === 0) { return init; } let acc = init; for (let k = 0; k < numsLength; k++) { acc = fn(acc, nums[k]); } return acc; }; #JavaScript #DSA #CodingPractice #100DaysOfCode #FrontendDevelopment #ProblemSolving

🚀 Day 4 of my JavaScript Coding Practice Today’s problem: Two Sum var twoSum = function(nums, target) { const map = new Map(); // Store: { value : index } for (let i = 0; i < nums.length; i++) { const complement = target - nums[i]; // If the needed number is already in our map, we found the pair! if (map.has(complement)) { return [map.get(complement), i]; } // Otherwise, save the current number and its index map.set(nums[i], i); } return []; // Return empty if no pair is found }; 💡 Instead of using brute force (O(n²)), I used a HashMap approach to solve it in O(n) time. Key takeaway: Understanding how to trade space for time can significantly optimize performance. Small steps every day → Big improvements over time 📈 #JavaScript #DSA #CodingPractice #100DaysOfCode #FrontendDevelopment

Day 6 / 30 - JavaScript Coding Practice Today’s problem: Roman to Integer var romanToInt = function (s) { if (s.length > 15) { return; } const romanMap = new Map([ ['I', 1], ['V', 5], ['X', 10], ['L', 50], ['C', 100], ['D', 500], ['M', 1000] ]); let sum = 0; let preValue = 0; for (let k = s.length - 1; k >= 0; k--) { let currentVal = romanMap.get(s[k]); if (currentVal < preValue) { sum -= currentVal; } else { sum += currentVal; } preValue = currentVal; } return sum; }; 💡 Key Insight: Instead of scanning from left to right, I iterated from right to left to easily handle subtraction cases like IV (4) and IX (9). 👉 If a smaller value comes before a larger one → subtract 👉 Otherwise → add #JavaScript #DSA #CodingPractice #ProblemSolving #100DaysOfCode #FrontendDevelopment

Day 10 / 30 - Javascript Coding Challenge Problem: Given an array of functions [f1, f2, f3, ..., fn], return a new function fn that is the function composition of the array of functions. The function composition of [f(x), g(x), h(x)] is fn(x) = f(g(h(x))). The function composition of an empty list of functions is the identity function f(x) = x. You may assume each function in the array accepts one integer as input and returns one integer as output. Solution: var compose = function (functions) { return function (x) { let sum = x; for (let k = functions.length - 1; k >= 0; k--) { sum = functions[k](sum) } return sum } }; #JavaScript #FunctionalProgramming #DSA #CodingPractice #100DaysOfCode #FrontendDevelopment

 Day 17 / 30 – JavaScript Coding Challenge Problem: Remove duplicates in-place from a sorted array and return the count of unique elements. Solution: var removeDuplicates = function (nums) {     if (nums.length === 0) return 0;     let i = 0;     for (let j = 0; j < nums.length; j++) {         if (nums[j] !== nums[i]) {             i++;             nums[i] = nums[j];         }     }     return i + 1; }; #JavaScript #DSA #CodingPractice #100DaysOfCode #ProblemSolving #FrontendDevelopment

Scope vs Closure in JavaScript — Explained Simply Understanding the difference between Scope and Closure is crucial for writing clean and efficient JavaScript code. While Scope defines where variables are accessible, Closure allows functions to remember their lexical environment even after execution. This concept is widely used in: • Data encapsulation • Function factories • Callbacks & async programming If you’ve ever been confused between these two, this guide will help you clear it with practical examples. 👉 Read the full article: https://lnkd.in/ga8WaNiA #JavaScript #FrontendDevelopment #WebDevelopment #Programming #Coding #SoftwareDevelopment #LearnJavaScript #InterviewPrep

One small word in JavaScript causes a lot of confusion: undefined. Many developers encounter it but don’t fully understand why it appears. In my latest article, I break it down in a practical way: • What undefined actually means • Common scenarios where it shows up • Mistakes developers often make • How to avoid it in real projects This is especially useful if you're learning JavaScript or improving your debugging skills. 🔗 Read the full article: https://lnkd.in/gaGDuAHp Curious — what was the most confusing JavaScript concept for you when you started? #JavaScript #WebDevelopment #FrontendDevelopment #Programming #Coding #SoftwareDevelopment #Debugging #LearnJavaScript

Some JavaScript concepts sound simple but create confusion in real projects. One common example is Debounce vs Throttle. Both are used to control how frequently a function executes when events happen repeatedly, such as scrolling, resizing, or typing in an input field. Understanding the difference helps developers build better-performing and more responsive applications. In this article, I explained the concept with simple examples so developers can easily understand when to use Debounce and when to use Throttle. Read the article: Debounce vs Throttle in JavaScript https://lnkd.in/gK5NE4Cn #JavaScript #FrontendDevelopment #WebDevelopment #SoftwareDevelopment #Programming #Coding

Understanding the Event Loop in JavaScript is a turning point for every developer. Many developers use async features like promises, setTimeout, or async/await daily — but very few truly understand what happens behind the scenes. I’ve written a detailed yet easy-to-understand article that breaks down: ✔ Call Stack ✔ Callback Queue ✔ Microtask Queue ✔ Execution Order If you want to strengthen your JavaScript fundamentals and avoid common async mistakes, this will definitely help. 👉 Read the full article: https://lnkd.in/gDhwvmUc I’d love to hear your thoughts — what was the hardest concept for you when learning the Event Loop? #JavaScript #SoftwareDevelopment #WebDevelopment #FrontendDevelopment #AsyncProgramming #Coding #TechLearning